Method and apparatus for performing access control or membership verification for dual connectivity in wireless communication system

ABSTRACT

A method and apparatus for performing access control and/or membership verification for dual connectivity in a wireless communication system is provided. A first evolved NodeB (eNB) transmits a closed subscriber group (CSG) membership status of a user equipment (UE) to a second eNB, which is a home eNB (HeNB), and receives at least one of a CSG identifier (ID) or a cell access mode of the second eNB from the second eNB. A mobility management entity (MME) may verify the CSG membership status of the UE and transmit the verified CSG membership status of the UE to the first eNB. And then, the first eNB transmits the verified CSG membership status of the UE to the second eNB.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the National Stage filing under 35 U.S.C. 371 ofInternational Application No. PCT/KR2015/007093, filed on Jul. 8, 2015,which claims the benefit of U.S. Provisional Application No. 62/021,721,filed on Jul. 8, 2014, 62/077,320, filed on Nov. 10, 2014 and62/143,830, filed on Apr. 7, 2015, the contents of which are all herebyincorporated by reference herein in their entirety.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to wireless communications, and moreparticularly, to a method and apparatus for performing home evolvedNodeB (HeNB) access control or membership verification for dualconnectivity in a wireless communication system.

Related Art

3rd generation partnership project (3GPP) long-term evolution (LTE) is atechnology for enabling high-speed packet communications. Many schemeshave been proposed for the LTE objective including those that aim toreduce user and provider costs, improve service quality, and expand andimprove coverage and system capacity. The 3GPP LTE requires reduced costper bit, increased service availability, flexible use of a frequencyband, a simple structure, an open interface, and adequate powerconsumption of a terminal as an upper-level requirement.

Small cells using low power nodes are considered promising to cope withmobile traffic explosion, especially for hotspot deployments in indoorand outdoor scenarios. A low-power node generally means a node whosetransmission power is lower than macro node and base station (BS)classes, for example pico and femto evolved NodeB (eNB) are bothapplicable. Small cell enhancements for evolved UMTS terrestrial radioaccess (E-UTRA) and evolved UMTS terrestrial radio access network(E-UTRAN) will focus on additional functionalities for enhancedperformance in hotspot areas for indoor and outdoor using low powernodes.

One of potential solutions for small cell enhancement, dual connectivityhas been discussed. Dual connectivity is used to refer to operationwhere a given UE consumes radio resources provided by at least twodifferent network points connected with non-ideal backhaul. Furthermore,each eNB involved in dual connectivity for a UE may assume differentroles. Those roles do not necessarily depend on the eNB's power classand can vary among UEs. Dual connectivity may be one of potentialsolutions for small cell enhancement.

A home eNB (HeNB) has been specified with both S1 and X2 mobilitypossible from 3GPP LTE rel-8 to rel-12. For HeNB, access control and/ormembership verification may be performed for S1/X2 mobility. A methodfor performing access control and/or membership verification, when theHeNB is used as a secondary eNB (SeNB) in dual connectivity, may berequired.

SUMMARY OF THE INVENTION

The present invention provides a method and apparatus for performinghome evolved NodeB (HeNB) access control or membership verification fordual connectivity in a wireless communication system. The presentinvention provides a method and apparatus for performing access controland/or membership verification when a HeNB is used as a secondary eNB(SeNB) in dual connectivity.

In an aspect, a method for performing, by a first evolved NodeB (eNB),access control in a wireless communication system is provided. Themethod includes transmitting a closed subscriber group (CSG) membershipstatus of a user equipment (UE) to a second eNB, which is a home eNB(HeNB), receiving at least one of a CSG identifier (ID) or a cell accessmode of the second eNB from the second eNB, and transmitting a verifiedCSG membership status of the UE to the second eNB.

In another aspect, a method for performing, by a second evolved NodeB(eNB) which is a home eNB (HeNB), access control in a wirelesscommunication system is provided. The method includes receiving a closedsubscriber group (CSG) membership status of a user equipment (UE) from afirst eNB, transmitting at least one of a CSG identifier (ID), a cellaccess mode of the second eNB, or a public land mobile network (PLMN) IDof the second eNB to the first eNB, and receiving a verified CSGmembership status of the UE from the first eNB.

When a HeNB is used as a SeNB in dual connectivity, access controland/or membership verification may be performed efficiently.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows LTE system architecture.

FIG. 2 shows a block diagram of architecture of a typical E-UTRAN and atypical EPC.

FIG. 3 shows a block diagram of a user plane protocol stack of an LTEsystem.

FIG. 4 shows a block diagram of a control plane protocol stack of an LTEsystem.

FIG. 5 shows an example of a physical channel structure.

FIG. 6 shows radio protocol architecture for dual connectivity.

FIG. 7 shows C-plane connectivity of eNBs involved in dual connectivityfor a certain UE.

FIG. 8 shows U-plane connectivity of eNBs involved in dual connectivityfor a certain UE.

FIG. 9 shows an example of U-plane architecture for dual connectivity.

FIG. 10 shows another example of U-plane architecture for dualconnectivity.

FIG. 11 shows an example of a SeNB addition procedure.

FIG. 12 shows an E-RAB modification indication procedure.

FIG. 13 shows dual connectivity when a HeNB takes role of a SeNB.

FIG. 14 shows an example of a method for performing access controland/or membership verification for dual connectivity according to anembodiment of the present invention.

FIG. 15 shows another example of a method for performing access controland/or membership verification for dual connectivity according to anembodiment of the present invention.

FIG. 16 shows another example of a method for performing access controland/or membership verification for dual connectivity according to anembodiment of the present invention.

FIG. 17 shows another example of a method for performing access controland/or membership verification for dual connectivity according to anembodiment of the present invention.

FIG. 18 shows another example of a method for performing access controland/or membership verification for dual connectivity according to anembodiment of the present invention.

FIG. 19 shows an example of a method for performing access controlaccording to an embodiment of the present invention.

FIG. 20 shows another example of a method for performing access controlaccording to an embodiment of the present invention.

FIG. 21 shows an example of a method for performing access controlaccording to an embodiment of the present invention.

FIG. 22 shows a wireless communication system to implement an embodimentof the present invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

The technology described below can be used in various wirelesscommunication systems such as code division multiple access (CDMA),frequency division multiple access (FDMA), time division multiple access(TDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), etc. The CDMA canbe implemented with a radio technology such as universal terrestrialradio access (UTRA) or CDMA-2000. The TDMA can be implemented with aradio technology such as global system for mobile communications(GSM)/general packet ratio service (GPRS)/enhanced data rate for GSMevolution (EDGE). The OFDMA can be implemented with a radio technologysuch as institute of electrical and electronics engineers (IEEE) 802.11(Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, evolved UTRA (E-UTRA), etc.IEEE 802.16m is an evolution of IEEE 802.16e, and provides backwardcompatibility with an IEEE 802.16-based system. The UTRA is a part of auniversal mobile telecommunication system (UMTS). 3rd generationpartnership project (3GPP) long term evolution (LTE) is a part of anevolved UMTS (E-UMTS) using the E-UTRA. The 3GPP LTE uses the OFDMA indownlink and uses the SC-FDMA in uplink. LTE-advance (LTE-A) is anevolution of the 3GPP LTE.

For clarity, the following description will focus on the LTE-A. However,technical features of the present invention are not limited thereto.

FIG. 1 shows LTE system architecture. The communication network iswidely deployed to provide a variety of communication services such asvoice over internet protocol (VoIP) through IMS and packet data.

Referring to FIG. 1, the LTE system architecture includes one or moreuser equipment (UE; 10), an evolved-UMTS terrestrial radio accessnetwork (E-UTRAN) and an evolved packet core (EPC). The UE 10 refers toa communication equipment carried by a user. The UE 10 may be fixed ormobile, and may be referred to as another terminology, such as a mobilestation (MS), a user terminal (UT), a subscriber station (SS), awireless device, etc.

The E-UTRAN includes one or more evolved node-B (eNB) 20, and aplurality of UEs may be located in one cell. The eNB 20 provides an endpoint of a control plane and a user plane to the UE 10. The eNB 20 isgenerally a fixed station that communicates with the UE 10 and may bereferred to as another terminology, such as a base station (BS), anaccess point, etc. One eNB 20 may be deployed per cell.

Hereinafter, a downlink (DL) denotes communication from the eNB 20 tothe UE 10, and an uplink (UL) denotes communication from the UE 10 tothe eNB 20. In the DL, a transmitter may be a part of the eNB 20, and areceiver may be a part of the UE 10. In the UL, the transmitter may be apart of the UE 10, and the receiver may be a part of the eNB 20.

The EPC includes a mobility management entity (MME) and a systemarchitecture evolution (SAE) gateway (S-GW). The MME/S-GW 30 may bepositioned at the end of the network and connected to an externalnetwork. For clarity, MME/S-GW 30 will be referred to herein simply as a“gateway,” but it is understood that this entity includes both the MMEand S-GW.

The MME provides various functions including non-access stratum (NAS)signaling to eNBs 20, NAS signaling security, access stratum (AS)security control, inter core network (CN) node signaling for mobilitybetween 3GPP access networks, idle mode UE reachability (includingcontrol and execution of paging retransmission), tracking area listmanagement (for UE in idle and active mode), packet data network (PDN)gateway (P-GW) and S-GW selection, MME selection for handovers with MMEchange, serving GPRS support node (SGSN) selection for handovers to 2Gor 3G 3GPP access networks, roaming, authentication, bearer managementfunctions including dedicated bearer establishment, support for publicwarning system (PWS) (which includes earthquake and tsunami warningsystem (ETWS) and commercial mobile alert system (CMAS)) messagetransmission. The S-GW host provides assorted functions includingper-user based packet filtering (by e.g., deep packet inspection),lawful interception, UE Internet protocol (IP) address allocation,transport level packet marking in the DL, UL and DL service levelcharging, gating and rate enforcement, DL rate enforcement based onaccess point name aggregate maximum bit rate (APN-AMBR).

Interfaces for transmitting user traffic or control traffic may be used.The UE 10 is connected to the eNB 20 via a Uu interface. The eNBs 20 areconnected to each other via an X2 interface. Neighboring eNBs may have ameshed network structure that has the X2 interface. A plurality of nodesmay be connected between the eNB 20 and the gateway 30 via an S1interface.

FIG. 2 shows a block diagram of architecture of a typical E-UTRAN and atypical EPC. Referring to FIG. 2, the eNB 20 may perform functions ofselection for gateway 30, routing toward the gateway 30 during a radioresource control (RRC) activation, scheduling and transmitting of pagingmessages, scheduling and transmitting of broadcast channel (BCH)information, dynamic allocation of resources to the UEs 10 in both ULand DL, configuration and provisioning of eNB measurements, radio bearercontrol, radio admission control (RAC), and connection mobility controlin LTE ACTIVE state. In the EPC, and as noted above, gateway 30 mayperform functions of paging origination, LTE_IDLE state management,ciphering of the user plane, SAE bearer control, and ciphering andintegrity protection of NAS signaling.

FIG. 3 shows a block diagram of a user plane protocol stack of an LTEsystem. FIG. 4 shows a block diagram of a control plane protocol stackof an LTE system. Layers of a radio interface protocol between the UEand the E-UTRAN may be classified into a first layer (L1), a secondlayer (L2), and a third layer (L3) based on the lower three layers ofthe open system interconnection (OSI) model that is well-known in thecommunication system.

A physical (PHY) layer belongs to the L1. The PHY layer provides ahigher layer with an information transfer service through a physicalchannel. The PHY layer is connected to a medium access control (MAC)layer, which is a higher layer of the PHY layer, through a transportchannel. A physical channel is mapped to the transport channel. Databetween the MAC layer and the PHY layer is transferred through thetransport channel. Between different PHY layers, i.e., between a PHYlayer of a transmission side and a PHY layer of a reception side, datais transferred via the physical channel.

A MAC layer, a radio link control (RLC) layer, and a packet dataconvergence protocol (PDCP) layer belong to the L2. The MAC layerprovides services to the RLC layer, which is a higher layer of the MAClayer, via a logical channel. The MAC layer provides data transferservices on logical channels. The RLC layer supports the transmission ofdata with reliability. Meanwhile, a function of the RLC layer may beimplemented with a functional block inside the MAC layer. In this case,the RLC layer may not exist. The PDCP layer provides a function ofheader compression function that reduces unnecessary control informationsuch that data being transmitted by employing IP packets, such as IPv4or IPv6, can be efficiently transmitted over a radio interface that hasa relatively small bandwidth.

A radio resource control (RRC) layer belongs to the L3. The RLC layer islocated at the lowest portion of the L3, and is only defined in thecontrol plane. The RRC layer controls logical channels, transportchannels, and physical channels in relation to the configuration,reconfiguration, and release of radio bearers (RBs). The RB signifies aservice provided the L2 for data transmission between the UE andE-UTRAN.

Referring to FIG. 3, the RLC and MAC layers (terminated in the eNB onthe network side) may perform functions such as scheduling, automaticrepeat request (ARQ), and hybrid ARQ (HARQ). The PDCP layer (terminatedin the eNB on the network side) may perform the user plane functionssuch as header compression, integrity protection, and ciphering.

Referring to FIG. 4, the RLC and MAC layers (terminated in the eNB onthe network side) may perform the same functions for the control plane.The RRC layer (terminated in the eNB on the network side) may performfunctions such as broadcasting, paging, RRC connection management, RBcontrol, mobility functions, and UE measurement reporting andcontrolling. The NAS control protocol (terminated in the MME of gatewayon the network side) may perform functions such as a SAE bearermanagement, authentication, LTE_IDLE mobility handling, pagingorigination in LTE_IDLE, and security control for the signaling betweenthe gateway and UE.

FIG. 5 shows an example of a physical channel structure. A physicalchannel transfers signaling and data between PHY layer of the UE and eNBwith a radio resource. A physical channel consists of a plurality ofsubframes in time domain and a plurality of subcarriers in frequencydomain. One subframe, which is 1 ms, consists of a plurality of symbolsin the time domain. Specific symbol(s) of the subframe, such as thefirst symbol of the subframe, may be used for a physical downlinkcontrol channel (PDCCH). The PDCCH carries dynamic allocated resources,such as a physical resource block (PRB) and modulation and coding scheme(MCS).

A DL transport channel includes a broadcast channel (BCH) used fortransmitting system information, a paging channel (PCH) used for paginga UE, a downlink shared channel (DL-SCH) used for transmitting usertraffic or control signals, a multicast channel (MCH) used for multicastor broadcast service transmission. The DL-SCH supports HARQ, dynamiclink adaptation by varying the modulation, coding and transmit power,and both dynamic and semi-static resource allocation. The DL-SCH alsomay enable broadcast in the entire cell and the use of beamforming.

A UL transport channel includes a random access channel (RACH) normallyused for initial access to a cell, a uplink shared channel (UL-SCH) fortransmitting user traffic or control signals, etc. The UL-SCH supportsHARQ and dynamic link adaptation by varying the transmit power andpotentially modulation and coding. The UL-SCH also may enable the use ofbeamforming.

The logical channels are classified into control channels fortransferring control plane information and traffic channels fortransferring user plane information, according to a type of transmittedinformation. That is, a set of logical channel types is defined fordifferent data transfer services offered by the MAC layer.

The control channels are used for transfer of control plane informationonly. The control channels provided by the MAC layer include a broadcastcontrol channel (BCCH), a paging control channel (PCCH), a commoncontrol channel (CCCH), a multicast control channel (MCCH) and adedicated control channel (DCCH). The BCCH is a downlink channel forbroadcasting system control information. The PCCH is a downlink channelthat transfers paging information and is used when the network does notknow the location cell of a UE. The CCCH is used by UEs having no RRCconnection with the network. The MCCH is a point-to-multipoint downlinkchannel used for transmitting multimedia broadcast multicast services(MBMS) control information from the network to a UE. The DCCH is apoint-to-point bi-directional channel used by UEs having an RRCconnection that transmits dedicated control information between a UE andthe network.

Traffic channels are used for the transfer of user plane informationonly. The traffic channels provided by the MAC layer include a dedicatedtraffic channel (DTCH) and a multicast traffic channel (MTCH). The DTCHis a point-to-point channel, dedicated to one UE for the transfer ofuser information and can exist in both uplink and downlink. The MTCH isa point-to-multipoint downlink channel for transmitting traffic datafrom the network to the UE.

Uplink connections between logical channels and transport channelsinclude the DCCH that can be mapped to the UL-SCH, the DTCH that can bemapped to the UL-SCH and the CCCH that can be mapped to the UL-SCH.Downlink connections between logical channels and transport channelsinclude the BCCH that can be mapped to the BCH or DL-SCH, the PCCH thatcan be mapped to the PCH, the DCCH that can be mapped to the DL-SCH, andthe DTCH that can be mapped to the DL-SCH, the MCCH that can be mappedto the MCH, and the MTCH that can be mapped to the MCH.

An RRC state indicates whether an RRC layer of the UE is logicallyconnected to an RRC layer of the E-UTRAN. The RRC state may be dividedinto two different states such as an RRC idle state (RRC_IDLE) and anRRC connected state (RRC_CONNECTED). In RRC_IDLE, the UE may receivebroadcasts of system information and paging information while the UEspecifies a discontinuous reception (DRX) configured by NAS, and the UEhas been allocated an identification (ID) which uniquely identifies theUE in a tracking area and may perform public land mobile network (PLMN)selection and cell re-selection. Also, in RRC_IDLE, no RRC context isstored in the eNB.

In RRC_CONNECTED, the UE has an E-UTRAN RRC connection and a context inthe E-UTRAN, such that transmitting and/or receiving data to/from theeNB becomes possible. Also, the UE can report channel qualityinformation and feedback information to the eNB. In RRC_CONNECTED, theE-UTRAN knows the cell to which the UE belongs. Therefore, the networkcan transmit and/or receive data to/from UE, the network can controlmobility (handover and inter-radio access technologies (RAT) cell changeorder to GSM EDGE radio access network (GERAN) with network assistedcell change (NACC)) of the UE, and the network can perform cellmeasurements for a neighboring cell.

In RRC_IDLE, the UE specifies the paging DRX cycle. Specifically, the UEmonitors a paging signal at a specific paging occasion of every UEspecific paging DRX cycle. The paging occasion is a time interval duringwhich a paging signal is transmitted. The UE has its own pagingoccasion. A paging message is transmitted over all cells belonging tothe same tracking area. If the UE moves from one tracking area (TA) toanother TA, the UE will send a tracking area update (TAU) message to thenetwork to update its location.

Overall architecture and network interface for dual connectivity (DC) isdescribed. It may be referred to 3GPP TR 36.842 V12.0.0 (2013-12). TheE-UTRAN may supports dual connectivity operation whereby a multipleRX/TX UE in RRC_CONNECTED is configured to utilize radio resourcesprovided by two distinct schedulers, located in two eNBs connected via anon-ideal backhaul over the X2 interface. The overall E-UTRANarchitecture described in FIG. 1 is applicable for dual connectivity aswell. Two different roles may be assumed to eNBs involved in dualconnectivity for a certain UE: an eNB may either act as a master eNB(MeNB) or as a secondary eNB (SeNB). The MeNB is the eNB whichterminates at least S1-MME in dual connectivity. The SeNB is the eNBthat is providing additional radio resources for the UE but is not theMeNB in dual connectivity. In dual connectivity a UE is connected to oneMeNB and one SeNB.

FIG. 6 shows radio protocol architecture for dual connectivity. In DC,the radio protocol architecture that a particular bearer uses depends onhow the bearer is setup. Three alternatives exist, master cell group(MCG) bearer, secondary cell group (SCG) bearer and split bearer.Referring to FIG. 6, those three alternatives are depicted, i.e. inorder of the MCG bearer, split bearer and SCG bearer from left to right.The MCG bearer is a bearer whose radio protocols are only located in theMeNB to use MeNB resources only in dual connectivity. The SCG bearer isa bearer whose radio protocols are only located in the SeNB to use SeNBresources in dual connectivity. The split bearer is a bearer whose radioprotocols are located in both the MeNB and the SeNB to use both MeNB andSeNB resources in dual connectivity. Signaling radio bearers (SRBs) arealways of the MCG bearer and therefore only use the radio resourcesprovided by the MeNB. The MCG is a group of serving cells associatedwith the MeNB, comprising of the primary cell (PCell) and optionally oneor more secondary cells (SCells) in dual connectivity. The SCG is agroup of serving cells associated with the SeNB, comprising of primarySCell (PSCell) and optionally one or more SCells in dual connectivity.DC may also be described as having at least one bearer configured to useradio resources provided by the SeNB.

FIG. 7 shows C-plane connectivity of eNBs involved in dual connectivityfor a certain UE. Inter-eNB control plane signaling for dualconnectivity is performed by means of X2 interface signaling. Controlplane signaling towards the MME is performed by means of S1 interfacesignaling. There is only one S1-MME connection per UE between the MeNBand the MME. Each eNB should be able to handle UEs independently, i.e.provide the PCell to some UEs while providing SCell(s) for SCG toothers. Each eNB involved in dual connectivity for a certain UE owns itsradio resources and is primarily responsible for allocating radioresources of its cells, respective coordination between MeNB and SeNB isperformed by means of X2 interface signaling. Referring to FIG. 7, theMeNB is C-plane connected to the MME via S1-MME, the MeNB and the SeNBare interconnected via X2-C.

FIG. 8 shows U-plane connectivity of eNBs involved in dual connectivityfor a certain UE. U-plane connectivity depends on the bearer optionconfigured. For MCG bearers, the MeNB is U-plane connected to the S-GWvia S1-U, the SeNB is not involved in the transport of user plane data.For split bearers, the MeNB is U-plane connected to the S-GW via S1-Uand in addition, the MeNB and the SeNB are interconnected via X2-U. ForSCG bearers, the SeNB is directly connected with the S-GW via S1-U. Ifonly MCG and split bearers are configured, there is no S1-U terminationin the SeNB.

FIG. 9 shows an example of U-plane architecture for dual connectivity.U-plane architecture for dual connectivity shown in FIG. 9 is thecombination of S1-U that terminates in SeNB and independent PDCPs (nobearer split). U-plane architecture for dual connectivity shown in FIG.9 may be called “Architecture 1A”.

FIG. 10 shows another example of U-plane architecture for dualconnectivity. U-plane architecture for dual connectivity shown in FIG.10 is the combination of S1-U that terminates in MeNB, bearer split inMeNB, and independent RLCs for split bearers. U-plane architecture fordual connectivity shown in FIG. 10 may be called “Architecture 3C”.

FIG. 11 shows an example of a SeNB addition procedure. The SeNB additionprocedure is initiated by the MeNB and is used to establish a UE contextat the SeNB in order to provide radio resources from the SeNB to the UE.This procedure is used to add at least the first cell (i.e. PSCell) ofthe SCG.

In step S1100, the MeNB decides to request the SeNB to allocate radioresources for a specific E-UTRAN radio access bearer (E-RAB), indicatingE-RAB characteristics (E-RAB parameters, transport layer network (TNL)address information corresponding to the UP option). In addition, theMeNB indicates within SCG-ConfigInfo the MCG configuration (includingsecurity algorithm for SCG bearer) and the entire UE capabilities for UEcapability coordination to be used as basis for the reconfiguration bythe SeNB, but does not include SCG configuration. The MeNB can providethe latest measurement results for the SCG cell(s) requested to beadded. The SeNB may reject the request. In contrast to SCG bearer, forthe split bearer option, the MeNB may either decide to request resourcesfrom the SeNB of such an amount, that the quality of service (QoS) forthe respective E-RAB is guaranteed by the exact sum of resourcesprovided by the MeNB and the SeNB together, or even more. The MeNBsdecision may be reflected in step S1101 below by the E-RAB parameterssignalled to the SeNB, which may differ from E-RAB parameters receivedover S1. The MeNB may request the direct establishment of SCG or splitbearer, i.e., without via MCG bearer.

If the radio resource management (RRM) entity in the SeNB is able toadmit the resource request, the SeNB allocates respective radioresources and, dependent on the bearer option, respective transportnetwork resources. The SeNB triggers random access so thatsynchronization of the SeNB radio resource configuration can beperformed. In step S1101, the SeNB provides the new radio resource ofSCG in SCG-Config to the MeNB. For SCG bearers, together with S1 DL TNLaddress information for the respective E-RAB and security algorithm, forsplit bearers X2 DL TNL address information. In case of split bearers,transmission of user plane data may take place after step S1101. In caseof SCG bearers, data forwarding and the SN Status Transfer may takeplace after step S1101.

If the MeNB endorses the new configuration, in step S1110, the MeNBsends the RRCConnectionReconfiguration message to the UE including thenew radio resource configuration of SCG according to the SCG-Config. TheUE applies the new configuration, and in step S1111, replies withRRCConnectionReconfigurationComplete message. In case the UE is unableto comply with (part of) the configuration included in theRRCConnectionReconfiguration message, the UE performs thereconfiguration failure procedure.

In step S1120, the MeNB informs the SeNB that the UE has completed thereconfiguration procedure successfully.

In step S1130, the UE performs synchronization towards the PSCell of theSeNB. The order the UE sends the RRCConnectionReconfigurationCompletemessage and performs the random access procedure towards the SCG is notdefined. The successful RA procedure towards the SCG is not required fora successful completion of the RRC connection reconfiguration procedure.

In case SCG bearers, and dependent on the bearer characteristics of therespective E-RAB, the MeNB may take actions to minimise serviceinterruption due to activation of dual connectivity (data forwarding instep S1140, SN status transfer in step S1150).

In step S1160, for SCG bearers, the path update procedure towards theEPC is performed. Specifically, in step S1161, the MeNB may transmit theE-RAB modification indication message to the MME. In step S1162, the MMEand S-GW may perform bearer modification. In step S1163, end markerpacket may be exchanged between S-GW and MeNB/SeNB. In step S1164, theMME may transmit the E-RAB the E-RAB modification confirmation messageto the MeNB.

FIG. 12 shows an E-RAB modification indication procedure. The E-RABmodification indication procedure corresponds to step S1161 and S1164 ofFIG. 11. The purpose of the E-RAB modification indication procedure isto enable the eNB to request modifications of already established E-RABsfor a given UE. The procedure uses UE-associated signaling.

In step S1200, the eNB initiates the procedure by sending an E-RABModification Indication message to the MME. The Transport Layer Addressinformation element (IE) and DL GTP TEID IE included in the E-RAB To BeModified Item IEs IE in the E-RAB Modification Indication message shallbe considered by the MME as the new DL address of the E-RABs. TheTransport Layer Address IE and DL GTP TEID IE included in the E-RAB NotTo Be Modified Item IEs IE in the E-RAB Modification Indication messageshall be considered by the MME as the E-RABs with unchanged DL address.

Table 1 shows an example of the E-RAB Modification Indication message.This message is sent by the eNB and is used to request the MME to applythe indicated modification for one or several E-RABs.

TABLE 1 IE type and Semantics Assigned IE/Group Name Presence Rangereference description Criticality Criticality Message Type M 9.2.1.1 YESreject MME UE S1AP ID M 9.2.3.3 YES reject eNB UE S1AP ID M 9.2.3.4 YESreject E-RAB to be 1 YES reject Modified List >E-RAB to Be 1 . . . EACHreject Modified Item IEs <maxnoofE-RABs> >>E-RAB ID M 9.2.1.2— >>Transport M 9.2.2.1 — Layer Address >>DL GTP TEID M GTP-TEID —9.2.2.2 E-RAB not to be 0 . . . 1 YES reject Modified List >E-RAB not toBe 1 . . . EACH reject Modified Item IEs <maxnoofE-RABs> >>E-RAB ID M9.2.1.2 — >>Transport M 9.2.2.1 — Layer Address >>DL GTP TEID M GTP-TEID— 9.2.2.2

In step S1210, the MME transmits an E-RAB Modification Confirmationmessage to the eNB. The E-RAB Modification Confirmation message shallcontain the result for all the E-RABs that were requested to be modifiedaccording to the E-RAB To Be Modified Item IEs IE of the E-RABModification Indication message as follows:

A list of E-RABs which are successfully modified shall be included inthe E-RAB Modify List IE.

A list of E-RABs which failed to be modified, if any, shall be includedin the E-RAB Failed to Modify List IE.

If the E-RAB Failed to Modify List IE is received in the E-RABModification Confirmation message, the eNB shall either:

-   -   release all corresponding E-UTRA and E-UTRAN resources for the        concerned E-RAB or    -   keep the previous transport information before sending the E-RAB        Modification Indication message unchanged for the concerned        E-RAB.

When the MME reports unsuccessful modification of an E-RAB, the causevalue should be precise enough to enable the eNB to know the reason foran unsuccessful modification.

Table 2 shows an example of the E-RAB Modification Confirmation message.This message is sent by the MME and is used to report the outcome of therequest from the E-RAB Modification Indication message.

TABLE 2 IE type and Semantics Assigned IE/Group Name Presence Rangereference description Criticality Criticality Message Type M 9.2.1.1 YESreject MME UE S1AP ID M 9.2.3.3 YES ignore eNB UE S1AP ID M 9.2.3.4 YESignore E-RAB Modify List 0 . . . 1 YES ignore >E-RAB Modify 1 . . . EACHignore Item IEs <maxnoofE-RABs> >>E-RAB ID M 9.2.1.2 — E-RAB Failed to OE-RAB A value for E- YES ignore Modify List List RAB ID shall 9.2.1.36only be present once in E-RAB Modify List IE + E-RAB Failed to ModifyList IE. Criticality O 9.2.1.21 YES ignore Diagnostics

FIG. 13 shows dual connectivity when a HeNB takes role of a SeNB. TheHeNB has been specified with both S1 and X2 mobility possible from 3GPPLTE rel-8 to rel-12, which may be a typical SeNB. Thus dual connectivitywith Macro eNB, as a MeNB, and HeNB, as a SeNB, is a considerablefeature for dual connectivity enhancement. However, the HeNB has threemodes (i.e. open mode, hybrid mode, closed mode), which makes dualconnectivity a little bit more complicated. For example, access controland/or membership verification problem still exists in dualconnectivity.

In order to solve the problem described above, a method for performingaccess control and/or membership verification for dual connectivityaccording to an embodiment of the present invention is described below.

FIG. 14 shows an example of a method for performing access controland/or membership verification for dual connectivity according to anembodiment of the present invention. It is assumed that the embodimentof FIG. 14 is based on the SeNB addition procedure which is shown inFIG. 11, however, the embodiment of the present invention is not limitedthereto. Other procedures may be used for the embodiment of the presentinvention. According to this embodiment of the present invention, afterthe MeNB makes a decision to add a SeNB, which is a HeNB, then the MeNBstarts the SeNB addition procedure as follows.

In step S1400, the MeNB transmits the SeNB Addition Request message witha closed subscriber group (CSG) membership status indication, whichindicates the CSG membership status of the UE, to the target SeNB, i.e.HeNB. The CSG membership status indication may be CSG Membership StatusIndication IE. Or, the CSG membership status indication may betransmitted via a new message or the other existing message.

Upon receiving the CSG membership status indication, the SeNB (HeNB)trusts the CSG membership status of the UE indicated by the received CSGmembership status indication. In step S1401, the SeNB (HeNB) transmitsthe SeNB Addition Request Acknowledge message, together with CSG IDand/or cell access mode of the target cell served by the SeNB (HeNB)and/or the PLMN ID of the target cell served by the SeNB (HeNB), to theMeNB. Or, CSG ID and/or cell access mode of the target cell and/or thePLMN ID of the target cell served by the SeNB (HeNB) may be transmittedvia a new message or the other existing message.

Thereafter, steps S1110 to S1150 of FIG. 11 may be performed as it is,since there is no change for those steps.

In step S1410, the MeNB transmits the E-RAB Modification Indicationmessage with CSG ID and/or cell access mode of the target cell and/orCSG membership status indication and/or the PLMN ID of the target cellserved by the SeNB (HeNB) to the MME, which will verify the CSGmembership status of the UE. Or, CSG ID and/or cell access mode of thetarget cell and/or CSG membership status indication and/or the PLMN IDof the target cell served by the SeNB (HeNB) may be transmitted via anew message or the other existing message. Step S1410 may be appliedonly to architecture 1A for dual connectivity shown in FIG. 9. Forarchitecture 3C for dual connectivity shown in FIG. 10, step S1410 maynot be necessary. Therefore, for architecture 3C for dual connectivity,the MeNB may transmit the E-RAB Modification Indication message (or anew message or other existing message) with CSG ID and/or cell accessmode of the target cell and/or CSG membership status indication and/orthe PLMN ID of the target cell served by the SeNB (HeNB) to the MMEearlier.

For split bearer option, the E-RAB Modification Indication message shownin Table 1 may be modified according to Table 3 below, in order toindicate the MME to ignore the modification about DL GTP ID andTransport Layer Address. Table 3 shows an example of the E-RABModification Indication message according to an embodiment of thepresent invention.

TABLE 3 IE type and Semantics Assigned IE/Group Name Presence Rangereference description Criticality Criticality Message Type M 9.2.1.1 YESreject MME UE S1AP ID M 9.2.3.3 YES reject eNB UE S1AP ID M 9.2.3.4 YESreject E-RAB to be 1 YES reject Modified List >E-RAB to Be 1 . . . EACHreject Modified Item IEs <maxnoofE-RABs> >>E-RAB ID M 9.2.1.2— >>Tranaport M 9.2.2.1 — Layer Address >>DL GTP TEID M GTP-TEID —9.2.2.2 >> Indication O To tell MME of ignoring this bearer is the notreally to modification be modified, this is for split bearer E-RAB notto be 0 . . . 1 YES reject Modified List >E-RAB not to Be 1 . . . EACHreject Modified Item IEs <maxnoofE-RABs> >>E-RAB ID M 9.2.1.2— >>Transport M 9.2.2.1 — Layer Address >>DL GTP TEID M GTP-TEID —9.2.2.2

If the Indication of ignoring the modification IE is included in theE-RAB Modification Indication message, the MME may not treat theTransport Layer Address and DL GTP TEID IEs for the same E-RAB as to bemodified, which is not really modified for split bearer option.

In step S1420, the MME and S-GW may perform bearer modification. In stepS1430, end marker packet may be exchanged between S-GW and MeNB/SeNB(HeNB).

Upon receiving the CSG ID and/or cell access mode of the target celland/or CSG membership status indication and/or the PLMN ID of the targetcell served by the SeNB (HeNB) from the MeNB, the MME verifies the CSGmembership status of the UE. If the UE passes the verification, in stepS1440, the MME transmits the E-RAB Modification Confirmation messagewith the verified CSG membership status of the UE to the MeNB. Or, theverified CSG membership status of the UE may be transmitted via a newmessage or the other existing message. Step S1440 may be applied only toarchitecture 1A for dual connectivity. For architecture 3C for dualconnectivity, step S1440 may not be necessary. Therefore, forarchitecture 3C for dual connectivity, the MeNB may transmit the E-RABModification Confirmation message (or a new message or other existingmessage) with the verified CSG membership status of the UE to the MeNBearlier.

For split bearer option, the E-RAB Modification Confirmation messageshown in Table 2 may be modified according to Table 4 below, as aresponse to the E-RAB Modification Indication message shown in Table 3.Table 4 shows an example of the E-RAB Modification Confirmation messageaccording to an embodiment of the present invention.

TABLE 4 IE type and Semantics Assigned IE/Group Name Presence Rangereference description Criticality Criticality Message Type M 9.2.1.1 YESreject MME UE S1AP ID M 9.2.3.3 YES ignore eNB UE S1AP ID M 9.2.3.4 YESignore E-RAB Modify List 0 . . . 1 YES ignore >E-RAB Modify 1 . . . EACHignore Item IEs <maxnoofE-RABs> >>E-RAB ID M 9.2.1.2 — >> Indication OAs an response of split bearer of new IE in the table above E-RAB Failedto O E-RAB A value for E- YES ignore Modify List List RAB ID shall9.2.1.36 only be present once in E-RAB Modify List IE + E-RAB Failed toModify List IE. Criticality O 9.2.1.21 YES ignore Diagnostics

The corresponding E-RAB shall be included in the E-RAB Modify List IE ofthe E-RAB Modification Confirm message, which may be realized with a newindication.

Alternatively, if the UE does not pass the verification, in step S1440,the MME may transmit a failure message (or a new message or otherexisting message) with the verified CSG membership status of the UE tothe MeNB. Or, the MME may transmit the E-RAB Modification Confirmationmessage (or a new message or other existing message) with the CSGmembership status, which indicates that the UE is not a member. StepS1440 may be applied only to architecture 1A for dual connectivity. Forarchitecture 3C for dual connectivity, step S1440 may not be necessary.Therefore, for architecture 3C for dual connectivity, the MeNB maytransmit the failure message (or a new message or other existingmessage) with the verified CSG membership status of the UE to the MeNBearlier.

In step S1450, the MeNB may transmit a new message (or existing messagewith new IEs) to notify the SeNB of the final CSG membership status ofthe UE. If the target cell is hybrid mode, the SeNB may treat the UE asa member when CSG membership status is true. Otherwise, the SeNB maydowngrade the UE as a non-member or disconnect the UE, and the SeNB mayupdate the UE context for this UE about the CSG membership status. Ifthe target cell is close mode, the SeNB may treat the UE as a memberwhen CSG membership status is true. Otherwise, the SeNB may release thisbearer.

If the verification failure happens, i.e. the UE does not pass theverification, in step S1450, the MeNB initiates SeNB release with acause value to indicate the SeNB the reason of the failure. Or, the MeNBmay indicate the SeNB to treat the UE as a non-member.

FIG. 15 shows another example of a method for performing access controland/or membership verification for dual connectivity according to anembodiment of the present invention. FIG. 15 corresponds to a case whenthe verification failure happens. Steps S1500 to S1510 are the same assteps S1400 to S1410 of FIG. 14.

In step S1520, the MME verifies the CSG membership status of the UEand/or performs access control.

If the verification failure happens for the UE, in step S1530, the MMEtransmits a failure message (e.g., E-RAB Modification Failure message orother message) with the verified CSG membership status, which indicatesa non-member, to the MeNB. Or, the MME may transmit the E-RABModification Confirmation message with the CSG membership status, whichindicates that the UE is not a member. For architecture 3C for dualconnectivity, step S1510 and S1530 may be means totally new messages.The MME may not trigger the Dedicated Bearer Deactivation procedure forthe corresponding E-RABs to the SeNB (membership verification failed).

Upon receiving the E-RAB Failure message, in step S1540, the MeNB mayperform one of the followings.

(1) The MeNB may trigger the S1 UE Context Release procedure, upon whichall of UE bearers may be released.

(2) If the MeNB adds bearer to the SeNB, the MeNB may cancel theaddition decision, which means that the MeNB keeps serving the E-RABswith the old GPRS tunneling protocol (GTP) tunnels.

(3) If the SeNB is a hybrid mode, the MeNB may hold on the additiondecision and offload the E-RAB to the SeNB, which may treat the UE as anon-member.

In step S1550, the MeNB may transmit the SeNB Release message or X2 UEContext Release message to the SeNB with cause value to notify the SeNB.Alternatively, in step S1550, the MeNB may notify the SeNB the CSGmembership status of the UE if the SeNB is a hybrid mode. Accordingly,the SeNB may treat the UE as a non-member.

FIG. 16 shows another example of a method for performing access controland/or membership verification for dual connectivity according to anembodiment of the present invention. FIG. 16 also corresponds to a casewhen the verification failure happens. Steps S1600 to S1610 are the sameas steps S1400 to S1410 of FIG. 14.

In step S1620, the MME verifies the CSG membership status of the UEand/or performs access control. If the verification failure happens forthe UE, the MME may trigger the S1 UE Context Release procedure directlywith cause value, upon which all of UE bearers may be released. Or, theMME may trigger the MME-initiated detach procedure with cause value. Thecause value may indicate the CSG membership verification/access controlfailure.

In step S1630, the MeNB may transmit the SeNB Release message or X2 UEContext Release message to the SeNB with cause value to notify the SeNB.

FIG. 17 shows another example of a method for performing access controland/or membership verification for dual connectivity according to anembodiment of the present invention. It is assumed that the embodimentof FIG. 17 is also based on the SeNB addition procedure which is shownin FIG. 11, however, the embodiment of the present invention is notlimited thereto. Other procedures may be used for the embodiment of thepresent invention. According to this embodiment of the presentinvention, after the MeNB makes a decision to add a SeNB, which is aHeNB, the MeNB first initiates the request of access control and/ormembership verification to the MME and then starts the SeNB additionprocedure as follows.

In step S1700, the MeNB transmits the request of access control ormembership verification with target cell ID, CSG ID, and/or access modeof the target cell, and/or CSG membership status of the UE (reported bythe UE) to the MME. The target cell ID, CSG ID, and/or access mode ofthe target cell may be obtained by the MeNB through the X2 setuprequest/response messages earlier. Then, the MME may perform accesscontrol or membership verification.

In step S1710, after verifying the CSG membership status of the UE, theMME notifies the verified result about whether the UE passes the accesscontrol or not to the MeNB. That is, the MME may transmit the CSGmembership status of the UE, which indicates that the UE is a member ornot a member. The verified result may be transmitted via an existingmessage, or a new message, or an IE in the existing/new message.

In step S1720, the MeNB transmits the SeNB Addition Request message witha CSG membership status indication to the SeNB (HeNB). The CSGmembership status indication indicates that the UE is a member or not amember, which is indicated by the received verified result. The CSGmembership status indication may be CSG Membership Status Indication IE.Accordingly, the SeNB (HeNB) may treat the UE as a member or non-member,depending on the received CSG membership status indication.

Then, the normal SeNB addition procedure may be performed. That is,steps S1101 to S1164 of FIG. 11 may be performed as it is, since thereis no change for those steps.

FIG. 18 shows another example of a method for performing access controland/or membership verification for dual connectivity according to anembodiment of the present invention. According to this embodiment of thepresent invention, the MeNB may get list of CSG membership status of theUE, which corresponds to each neighbor HeNB cell of the MeNB.Specifically, the MeNB may get the list of neighbor HeNB cell IDs,and/or CSG IDs, and/or list of access modes of the HeNB cell through X2Setup/Response messages.

In step S1800, the MeNB may provide the list of CSG membership status ofthe UE to the MME by Initial UE message, Uplink NAS message or othermessages, when the UE attaches, or request a new service or otherprocedures. Or, the MME may have the neighbor HeNB cell IDs of the MeNB,and/or CSG IDs, and/or list of access modes of the HeNB cell.

Upon receiving the list of CSG membership status of the UE, the MMEchecks the CSG membership status of the UE, which corresponds to eachHeNB cell ID. In step S1810, the MME may provide the whole list of theCSG membership status of the UE to the MeNB by one of the InitialContext Setup Request message, UE Context Modification Request message,S1 Handover Request message, Path Switch Request Acknowledge message orother messages depending on different procedures.

Upon receiving the list of the CSG membership status of the UE, the MeNBmay keep the list and be ready to use it later, depending on to whichtarget cell the MeNB will perform the SeNB addition procedure. In stepS1820, the MeNB transmits the SeNB Addition Request message with a CSGmembership status indication to the SeNB (HeNB). Then, the normal SeNBaddition procedure may be performed. That is, steps S1101 to S1164 ofFIG. 11 may be performed as it is, since there is no change for thosesteps.

FIG. 19 shows an example of a method for performing access controlaccording to an embodiment of the present invention.

In step S1900, the first eNB transmits a CSG membership status of a UEto a second eNB, which is a HeNB. The CSG membership status of the UEmay be transmitted via a SeNB addition request message.

In step S1910, the first eNB receives at least one of a CSG ID or a cellaccess mode of the second eNB from the second eNB. The at least one ofthe CSG ID or the cell access mode of the second eNB may be received viaa SeNB addition request acknowledge message. The cell access mode of thesecond eNB may be a hybrid mode.

The first eNB may further transmit at least one of the CSG ID, the cellaccess mode of the second eNB, or the CSG membership status of the UE toa MME, via an E-RAB modification indication message. The E-RABmodification indication message may include an indication of ignoringmodification of E-RABs for split bearer for dual connectivity. The firsteNB may further receive a verified CSG membership status of the UE froma MME, via an E-RAB modification confirmation message.

In step S1920, the first eNB transmits the verified CSG membershipstatus of the UE to the second eNB.

FIG. 20 shows another example of a method for performing access controlaccording to an embodiment of the present invention.

In step S2000, the second eNB, which is a HeNB, received a CSGmembership status of a UE from a first eNB. The CSG membership status ofthe UE may be received via a SeNB addition request message.

In step S2010, the second eNB transmits at least one of a CSG ID or acell access mode of the second eNB to the first eNB. The at least one ofthe CSG ID or the cell access mode of the second eNB may transmittedreceived via a SeNB addition request acknowledge message. The cellaccess mode of the second eNB may be a hybrid mode.

In step S2010, the second eNB receives a verified CSG membership statusof the UE from the first eNB. The second eNB may treat the UE as amember when the CSG membership status of the UE and the verified CSGmembership status of the UE are identical. Or, the second eNB may treatthe UE as a non-member when the CSG membership status of the UE and theverified CSG membership status of the UE are not identical.

FIG. 21 shows an example of a method for performing access controlaccording to an embodiment of the present invention.

In step S2100, the first eNB transmits a CSG membership status of a UEto a second eNB, which is a HeNB. The CSG membership status of the UEmay be transmitted via a SeNB addition request message.

In step S2110, the second eNB transmits at least one of a CSG ID or acell access mode of the second eNB from the second eNB. The at least oneof the CSG ID or the cell access mode of the second eNB may betransmitted via a SeNB addition request acknowledge message. The cellaccess mode of the second eNB may be a hybrid mode.

In step S2120, the first eNB may transmit at least one of the CSG ID,the cell access mode of the second eNB, or the CSG membership status ofthe UE to a MME via an E-RAB modification indication message. The E-RABmodification indication message may include an indication of ignoringmodification of E-RABs for split bearer for dual connectivity.

In step S2130, the MME may receive a verified CSG membership status ofthe UE from the MME via an E-RAB modification confirmation message.

In step S2140, the first eNB transmits the verified CSG membershipstatus of the UE to the second eNB.

FIG. 22 shows a wireless communication system to implement an embodimentof the present invention.

A MeNB 2200 includes a processor 2201, a memory 2202, and a transceiver2203. The processor 2201 may be configured to implement proposedfunctions, procedures, and/or methods in this description. Layers of theradio interface protocol may be implemented in the processor 2201. Thememory 2202 is operatively coupled with the processor 2201 and stores avariety of information to operate the processor 2201. The transceiver2203 is operatively coupled with the processor 2201, and transmitsand/or receives a radio signal.

A SeNB or MME 2210 includes a processor 2211, a memory 2212 and atransceiver 2213. The processor 2211 may be configured to implementproposed functions, procedures and/or methods described in thisdescription. Layers of the radio interface protocol may be implementedin the processor 2211. The memory 2212 is operatively coupled with theprocessor 2211 and stores a variety of information to operate theprocessor 2211. The transceiver 2213 is operatively coupled with theprocessor 2211, and transmits and/or receives a radio signal.

The processors 2201, 2211 may include application-specific integratedcircuit (ASIC), other chipset, logic circuit and/or data processingdevice. The memories 2202, 2212 may include read-only memory (ROM),random access memory (RAM), flash memory, memory card, storage mediumand/or other storage device. The transceivers 2203, 2213 may includebaseband circuitry to process radio frequency signals. When theembodiments are implemented in software, the techniques described hereincan be implemented with modules (e.g., procedures, functions, and so on)that perform the functions described herein. The modules can be storedin memories 2202, 2212 and executed by processors 2201, 2211. Thememories 2202, 2212 can be implemented within the processors 2201, 2211or external to the processors 2201, 2211 in which case those can becommunicatively coupled to the processors 2201, 2211 via various meansas is known in the art.

In view of the exemplary systems described herein, methodologies thatmay be implemented in accordance with the disclosed subject matter havebeen described with reference to several flow diagrams. While forpurposed of simplicity, the methodologies are shown and described as aseries of steps or blocks, it is to be understood and appreciated thatthe claimed subject matter is not limited by the order of the steps orblocks, as some steps may occur in different orders or concurrently withother steps from what is depicted and described herein. Moreover, oneskilled in the art would understand that the steps illustrated in theflow diagram are not exclusive and other steps may be included or one ormore of the steps in the example flow diagram may be deleted withoutaffecting the scope and spirit of the present disclosure.

What is claimed is:
 1. A method, by a first evolved NodeB (eNB) in awireless communication system, for establishing dual connectivity for auser equipment (UE) between the first eNB and a second eNB, the methodcomprising: while maintaining a connection with the UE, establishing thedual connectivity between the UE and each of the first eNB and thesecond eNB, the establishing comprising: transmitting a secondary eNB(SeNB) addition request message including a closed subscriber group(CSG) membership status of a user equipment (UE) directly to a secondeNB, which is a home eNB (HeNB); and receiving a SeNB additionacknowledge message directly from the second eNB as a response to theSeNB addition request message; and after the dual connectivity isestablished: transmitting a CSG identifier (ID) of the second eNB andthe CSG membership status of the UE to a mobility management entity(MME); receiving a verified CSG membership status of the UE from theMME; and transmitting the verified CSG membership status of the UE tothe second eNB.
 2. The method of claim 1, wherein the CSG ID of thesecond eNB and the CSG membership status of the UE is transmitted via anE-UTRAN radio access bearer (E-RAB) modification indication message. 3.The method of claim 2, wherein the E-RAB modification indication messageincludes an indication of ignoring modification of E-RABs for splitbearer for dual connectivity.
 4. The method of claim 1, wherein theverified CSG membership status of the UE is received via an E-RABmodification confirmation message.
 5. The method of claim 1, wherein theCSG membership status of the UE transmitted by the first eNB is trustedby the second eNB.
 6. The method of claim 2, wherein the E-RABmodification indication message further includes a cell access mode ofthe second eNB.
 7. The method of claim 2, wherein the E-RAB modificationindication message further includes a public land mobile network (PLMN)ID.
 8. The method of claim 1, wherein the verified CSG membership statusof the UE is transmitted to the second eNB if a CSG membership status ofthe UE and the verified CSG membership status are different from eachother.
 9. The method of claim 1, wherein the first eNB is a master eNBin dual connectivity, and wherein the second eNB is a secondary eNB(SeNB) in dual connectivity.
 10. The method of claim 1, wherein, afterthe dual connectivity is established, the method further comprises:maintaining the connection with the UE whether or not the secondary eNBcancels the dual connectivity based on the transmitted verified CSGmembership status.
 11. The method of claim 1, wherein, after the dualconnectivity is established, the method further comprises: maintainingthe connection with the UE whether or not the secondary eNB maintainsthe dual connectivity with the UE as a non-member based on thetransmitted verified CSG membership status.
 12. The method of claim 1,wherein the dual connectivity comprises one of a) a split bearerconnectivity, or b) a secondary cell group bearer connectivity.
 13. Amethod, by a second evolved NodeB (eNB) which is a home eNB (HeNB) in awireless communication system, for establishing dual connectivity for auser equipment (UE) between a first eNB and the second eNB, the methodcomprising: receiving a secondary eNB (SeNB) addition request messageincluding a closed subscriber group (CSG) membership status of a userequipment (UE) directly from a first eNB; transmitting a SeNB additionacknowledge message directly to the first eNB as a response to the SeNBaddition request message; trusting the CSG membership status of the UE;and receiving a verified CSG membership status of the UE from the firsteNB.
 14. The method of claim 13, further comprising treating the UE as amember when the verified CSG membership status of the UE is true. 15.The method of claim 13, further comprising when the verified CSGmembership status of the UE is not true: downgrading the UE as anon-member or disconnecting the UE; and updating a UE context for the UEabout the CSG membership status.
 16. The method of claim 13, wherein thefirst eNB is a master eNB in dual connectivity, and wherein the secondeNB is a secondary eNB (SeNB) in dual connectivity.
 17. The method ofclaim 13, wherein the dual connectivity comprises one of a split bearerconnectivity, or a secondary cell group bearer connectivity.
 18. A firstevolved NodeB (eNB) configured to establish dual connectivity for a userequipment (UE) between the first eNB and a second eNB in a wirelesscommunication system, the first eNB comprising: a transceiver; and aprocessor operatively connected to the transceiver, the processorconfigured to: while maintaining a connection with the UE, establish thedual connectivity between the UE and each of the first eNB and thesecond eNB, the establishing comprising: transmit a secondary eNB (SeNB)addition request message including a closed subscriber group (CSG)membership status of a user equipment (UE) directly to a second eNB,which is a home eNB (HeNB); and receive a SeNB addition acknowledgemessage directly from the second eNB as a response to the SeNB additionrequest message; and after the dual connectivity is established:transmit a CSG identifier (ID) of the second eNB and the CSG membershipstatus of the UE to a mobility management entity (MME); receive averified CSG membership status of the UE from the MME; and transmit theverified CSG membership status of the UE to the second eNB.